This section is from the book "Popular Law Library Vol7 Equity Jurisprudence, Trusts, Equity Pleading", by Albert H. Putney. Also available from Amazon: Popular Law-Dictionary.
A bill to take testimony de bene esse is for the purpose of obtaining testimony in a pending suit, and may be brought by either complainant or defendant. Bills of this character were discussed in the case of Richter vs. Jerome,3 the decision in which case was in part as follows:
"To entitle the party to maintain a bill of this description the plaintiff must aver: (1) That there is a suit depending in which the testimony of the witnesses named will be material. Story, Eq., Sec. 307. (2) That the suit is in such condition that the depositions cannot be taken in the ordinary methods prescribed by law, and that the aid of the court of equity is necessary to perpetuate testimony. (3) The facts which the plaintiff expects to prove by the testimony of the witnesses sought to be examined, that the court may see that they are material to the controversy. (4) The necessity for taking the testimony, and the danger that it may be lost by delay.
"A failure to make the proper averment in any of these particulars is good ground for a demurrer, but we do not understand that as a rule the allegations of the bill can be put in issue by an answer. In cases of bills strictly to perpetuate testimony (which will only lie when suit has been commenced) the defendant may allege by way of plea any fact that may tend to show that there is no occasion to perpetuate the testimony; as for instance, that there exists no such dispute or controversy as that alleged in the bill, or that the plaintiff has no such interest in it as will justify his application to perpetuate the testimony. Story, Eq. Pl., 306a. But in bills to take testimony de bene esse there must be a suit depending in some court, and this of itself is evidence of a controversy between the parties. In Ellice vs. Roupell, Story, Eq. PL, 306a note, Sir J. Romilly stated the rule to be in regard to bills for perpetuating testimony that defendant, by consenting to answer the plaintiff's bill, admitted his right to examine witnesses in the case, and that implies all that is demandable. 'For if there is really any bona fide controversy between the parties, the right to perpetuate the testimony follows as a matter of course.' In a case of the kind under consideration, where a hearing cannot be had in the supreme court in less than two or three years, and the witnesses are some of them old and infirm, it is obvious that the plaintiff ought in some way or another to be able to secure their testimony against the contingency of death, absence, or mental alienation. At the same time resort ought not to be had to the extraordinary power of a court of equity, if the usual methods of procedure prescribed by statute are competent to afford relief. The case is no longer 'depending/ in the circuit court, and hence is removed from the operation of the act of Congress permitting depositions to be taken de bene esse. Rev. St., Sec. 863. From the time the appeal was perfected, the jurisdiction of the circuit court was suspended, and so remains until the cause is remanded from the appellate court. Slaughter-house Cases, 10 Wall., 273. It has also been expressly held that this act has no application to cases pending in the Supreme Court. The Argo, 2 Wheat., 287."
3 25 Fed. Rep., 679.